Apparatus for measuring and indicating the flow of gases



May 31,1927. 1,630,307

H. Y. NoRwooD E1' AL APPARATUS lFOR MEASURING AND I-NDICATING THE FLow 0F GASES Filed Aug. 4,' 1925 Patterned HARRY Y. NORWOOD, OE AVON, ANn KENNETH L. TATE, OE ROCHESTER, NEW YORK, AssIGNORs To TAYLOR INSTRUMENT COMPANIES, OE ROCHESTER, NEW YORK, A

COBPORTION OF NEW YORK.

APPARATUS FOB MEASUBING AND INDICATING THE FLOW 0F GASES.

Application led August 4, 1925. Serial No. 48,170.

This invention relates -to apparatus for measuring and indicating the tow ot a gas, more especially as a function of some variable to be observed, such as the temperature, composition or other: characteristic of gas, one object of the invention being to provide the combination with a simple and practical apparatus of this nature adapted to accurately measuregaseous flow mdependently of close regulation of the operating pressures, of mechanism for indicatin the same on a dial in convenient terms suc for example, as those of the variable to be observed. Another object is the provision of such an apparatus in which use is made ofthe principle of maximum flow for eliminating in a simpleimanner the effect of tiuctuations in the operating pressures, together with mechanism for continuously indicating and recording thel desired variable. A further object is to provide an apparatus of the above character particularly adapted for in-P i' dicating temperatures and more especially for use as a pyrometer. o

To these and other ends 'the invention resides in certain improvements and combinations of parts, all' as will be hereinafter more fully described, the novel features being pointed out in the claim at the end of the specification.

In the drawings Figure 1 is an elevation, partly in section, of an apparatus embodying the present in vention;

Figure .2 is an enlarged .sectional view of' parts shown in Figure l;

Figure 3 is a further enlargement of a portion shown in Figure 2;

Figure 4 is 'an enlarged sectional detaill of one of the restricted passages of the gas chamber, and

Figure 5 is a sectional view on the line .5L-5 in Figure 4.

Similar reference numerals throughout the several views indicate the saine parts.

ri'he embodiment of the invention hereinv disclosed by way of illustation, represents an application of the same to the measurement of temperatures and, more especially to pyrometric measurements, comprising in the present instance .a tubular gas chamber 10, Figure f2, preferably constructed of porcelain or other heat resisting material. One

end of this member Or chamber is mounted for subjecting its Opposite epd to the tem-y perature to be measured.

Chamber 10 is provided with restricted inlet and outlet-1v passages, the inlet boing in the present instance located at the end sub jected to the temperature to be measured. This inlet passage is ypreferably in the form of a capillary boie for producingtranspirs atory flow ofA the gasin its passage theref through. And this bore is ormed'in the present instance by reduction in the bore of the chamber adjacent its end, as shown at 16.

The other, and in the present instance, the Outlet passage of the chamber, is provided at the opposite end of the bore of the chamber extension 11 and this outlet is preferably in the form of an etfusion orifice. An advantageous form of construction forthis orifice comprises a sleeve 1T .threadedly engaged in the end of extension 11 and having mounted therein the orifice member proper, for which a center jewel 18, such as used in watches, having an opening of -suitable diameter, has been found to serve advantageously. v

T heoperating pressures for causing flow of the gas, in the present instance air, to the' chamber are preferably obtained by subjecting the inlet passage to atmospheric pressure and connecting with theoutlet passage a pipe 19 leading to an exliauster, or pump 20, adapted to maintain a partial lvacuum of say 2 pounds per square inch or less, absolute. `The supply ot' air for the chamber inlet is preferably obtained from room atmosphere, to which end chamber l() is housed in a spaced outer chamber or porcelain sleeve 2l. closed. at its end adjacent theA chamber intake 1G. The other open end of sleeve 2l is mounted in the ,end of supporting sleeve 12. as shown, with the bore of which it communicates about the chamber 1t). Connected with the bore ot' sleeve 12. as b v means of a pipe 22, is a filter 23 of the usual or any lSuitable variety, located in the room atmosphere. It is apparent from this construction that air is drawn through the `filter, sleeve 21,'chamber inlet 16 and chamberoutlet 18 to the pump. It is to be noted that the air.

` temperature and flowing thence more slowly through chamber 10, becomes cooled at the outlet orifice to room temperature, so that temperature influence on the flow through the outlet orifice is substantially constant. In accordance 'with the principles of the transpiration of gases, the effect of increased temperature upon the How through the capillary inlet bore of the chamber tends to reduce such flow and hence to reduce the pressure in thechamber. The latter isv therefore a function of the temperature to be observed, or in other words a temperature sensitive pressure. f' v K It is essent.ial,',however, for utilizing the chamber pressure for measuring the transpiration temperature, that the difference in pressures to which the ends of the transpiration bore and hence the chamber are subjected be maintained independent of varia-y tions in the external operating pressures, or in other words in v the partial vacuum 'to which the outlet is externally subjected. This is effectively accomplished in a-simple f manner by the present invention through the 40 use of an outlet orifice constructed' or proportioned relative to the inlet, so as to maintain adiiference-in pressure on the o posite sides of the orifice adapted to utilize the known principle of maximum flow through the latter. Thatl is to say, if the external pressure on the orifice, or the partial vacuum, be maintainedless than one-pv half substantially, or more preciselv less than of the pressure in the cham er, a maximum or constant How occurs through the orifice, independently of fluctuations'in ,the partial vacuum within thefrange stated.

TheH dimensions ofthe parts will obviously vary withv variations in; structure-and use.` 55 within the principlesv defined. As merely illustrative in this respect, itmay be stated that successful ap hcation to pyrometric' work has been mage with a transpiration bore 2 inches long and .037 inches in diam- 00 eter and, an outlet orifice .021 inches in diameter, giving a substantial variation in chamber pressure for the working lrange of temperatures. The invention thusobviates the necessity for closeregulation of the operating pressures, which has -been'found a distance.

,end into a container 29 below `a liquid level .,stantial serious practical defect in prior a paratus of thisl class. The invention furt er .pro-

`vides for eliminating the influence of barometric changes upon measurement of the chamber pressure 'by the arrangement of the measuring apparatus as hereafter described. The inventlon provides the combination wit-h such an apparatus of indicating means for conveniently indicating, at any time, the pressure in the chamber, in terms of the desired variable of which it'is a function,'such as the furnace temperature. Such indicating means prefeiably comprises a recording mechanism, in the present instance a pressure recording instrument .of the known variety represented at 24 having a pressure responsive flexible .tube or diaphragm movl able rlesponsively to a pressure applied interiorly thereto for correspondingly moving a pen 25 over a time driven dial or chart 26, as well understood in the art. 'As the construction of the recording -instrument may be of any of the various types ,well known in the art, a detailed description of the`V same is unnecessary. The pressure responsive element or container of thel instrument is con-l nected directly as b means of a branch27 i of a pipe 27 a with c amber' 10 as shown and it is apparent from this arrangement that barometric variations are ,impressed upon the pressure sensitive element of the instrument 24, both externally by the. atmosphere and internally throughv the chamber and pipe 27 so that such changes counterbalance and` compensate for each. other without affecting the `accurate recording b the instrument o f the substantially in ependent temperature sensitive pressure of the chamber 10. The recorder chart however is preferably marked to read directl in terms of the temperature to be measure The indicating means comprises also an j I indicating device of relatively largeV scale adapted to be observed from a distance, so that a furnace or other temperature,`for example, may be conveniently watched from any p osition in the furnace room or other room in which an attendant may be stationed and so that comparatively small variations may bereadily observedl even from a It has been found that this can be effectively` accomplished by connecting .tube 27* with a glass tube 28 dipping at its lower therein subjected tor atmosphericpressurer 129 The reduction in pressure in chamber 10 1 causes a liquid column to rise in the tube to ya height proportional to the ressure in chamber 10 or in other words to t etemperature to be observed. By employin a. tube of substantial diameter ofbore, wit a rela tively Ii ht liquid adapted Ato rise to a sub; eight, and .providing a suitablescale 30 ,for the tube, reading directly vin temperatures, an, indicating -device is ob- 13 tained of such a nature that comparatively small changes of temperature may be easily and quickly observed at a considerable distance from the device so that close watch of the temperature is greatly facilitated. The invention thus afords a simple, practical and-efficient apparatus of the gaseous flow type for accurately indicating and recording in a continuous manner the temperature to which the apparatus is subjected and in terms of which the instrument dial or chart 26 is directly marked, and while the invention has been described in connection with the present embodiment as applied to the measurement of temperature, it is equally applicable to the measurement of other variables of which the gaseous flow or chamber pressure isa function'.

We claim as our invention:

In ap aratus for measuring temperatures, the com ination of a manonietric tube connected at one end to a body of liquid, a chamber having a capillary inlet and an effusion orifice outlet, means/'for maintaining a partial vacuum on-theiexterior of the outlet and a connection between the chamber andthe manometrc tube, the outlet orifice and the inlet being so roportioned that the external pressure on tllie orifice is less than .53 of the pressure in the chamber.

n Y HARRYv NORWOOD.

` KENNETH L. TATE.y 

